Method of making phonograph records



Dec. 2, 1930. F. L. DYER METHOD OF MAKING PHONOGRAPH RECORDS OrigihalFiled Oct.

INVENTOR Patented Dec. 2, 1930 PATENT], OFFICE rna vx'n DYER, or newYORK, N. Y.

METHOD OF MAKING PHONOGR APH RECORDS brig'inal applicatioii filedOctober 19, 1927, Serial 1T0. 227,191. Patent No. 1,726,546, datedSeptember 3, 1929. Divided and this application filed June 28, 1929.SerialNo. 374,314.

My invention relates to the art of makin phonograph records andespecially recor s which are capable of playing, without inter ruption,for long periods of time, as disclosed 5 in my Patents, No. 1,570,297 ofJanuary 19th,.

1926, and No. 1,628,658 of May 17th, 1927, and the present a plicationis a division of application filed ctober 19th, 1927, Serial No.227,191, issued as Patent No. 1,726,546, Sept. 3, 1929; n my patents,just referred to, I describe an improved talking machine record,hereafter referred to as a micro-record, employing a groove of greatlyreduced width, as compared withthe standard practice in vogue at thetime the applications for the same were filed, said micro-record beingmade at a surface speed substantially less than said standard, and beingpreferably of minute ampli- 20 tude so as to correspond substantially inits proportions to a standard record on a very reduced scale. In'thisway the increase in playing time will be greatly extended. As anexample, by forming a mlcro-record with a groove one one-thousandths ofan inch in width, five hundred threads to the inch, and recorded at amean surface speedof about eight inches per second, it becomes possibleto record on one face of a standard ten inch disk, selections of onehundred minutes in du ration. Therefore, on both sides of two suchdisks, it will be possible to record an entire book requiring almostseven hours in'whichto read it. The possibility of recording musicalselections will be correspondingly extended.

One diificulty presents itself in the making of these very long records.The task of reading continuously for upwards of an hour from printedpages is great. Almost inevitably mistakes will be made, such as theomission or mispronunciation of words, and if this occurs, the work hasto be started all over again on a fresh blank. Thesame is true in makinga long musical record, since a single false note would necessitate a newstart. M present invention is designed to overcome t e difficultyreferred to.

In carrying my improved method into effeet, I first make a series oforiginal records,

comprising in the aggregate the entire matter to be recorded,vwhethertalln'n or music. Each of these records will be, say ve minutes induration, so that in order to record for one hundred minutes on thesingle face of a ten inch disk, twenty of such ori al records will berequired. .Manifestly 52% original records may be shorter or longer thanfive minutes, the idea being that in case a mistake is made either inthe reading or the music, only a fraction of the entire recordedmaterial on one face of my improved micro-record will require tobevrepeated. Thus, in making a talking record of a book for example, itwill only be necessary for the reader to record a portion of thecontents thereof at one time, occupying only a few minutes, and in casean error is made, it becomes a simple matter to start again at the pointwhere the recorded matter on that particular record commenced.

The procedure to be followed in making a musical micro-record will beobvious, the or chestra, band, vocalist; or chorus simply making asuccession of records, one at a time, representing the successiveportions of the music to be recorded.

Preferably these original records, which in the aggregate comprise thematter to be transferred on one or both faces of-my improvedmicro-record, will be formed with a groove of standard width, surfacespeed and amplitude,thus permittin a very accurate recording of thesounds. This may be done in the old way or by modern electricalrecording methods as disclosed. for example in the patent to Vreelandand Dyer, No. 1,593,735 of July 27th, 1926.

My improved method next contemplates the transfer of the sounds from theseries of successive records to the face or faces of my improvedmicro-record. This transfer may be made from the original master recordsthemselves or from copies thereof made in the usual way in harder andmore durable material. It will be entirely feasible to make the transferfrom the original master records,'since it probably will not benecessary to run them more than once under the reproducing stylus and itis not important that there shall be great pressure on the reproducingstylus and therefore the wear will not be objectionably great. At thesame time it is perfectly feasible, though somewhat more expensive, toeffect the transfer from copies obtained in the usual way fromsuccessive masters. When the latter procedure is adopted it will bepossible to make any desired number of micro-masters, in case a verylarge number of copies of the improved micro-records are to be made.

In effecting a transfer from the successive records or copies to thedesired micro-master, it is necessary that there should be nosubstantial time interval between the records, because the micro-recordhas to be continuous, just as though it represented a long connectedreading or musical performance. In order to effect this result, Iperform the transferring o eration electrically by the use of pickup mecanism which transforms the record variations into telephone currentswhich are caused to actuate a magnetic recorder controlling the cuttingstylus. A pair of turntables will be used, on one of w ich will be themaster or copy from which the transfer is taking place to themicro-master and on the other turntable will be placed the successivemaster or copy'so that when the first record has been completed, it willbe only necessary to operate a simple electric switch and start thesecond turntable. The only interval of time between succeeding recordstherefore, will be the second or two necessary for the second turntableto reach its operating speed. This may represent the time intervalbetween successive paragraphs or chapters of a book or correspondingportions of a musical selection.

Furthermore, in my improved method I prefer to operate both the originalmasters or copies and the micro-master at speeds substantially belownormal. For example, if the normal shaft speed of a standard master iseighty revolutions per minute and the standard shaft speed of themicro-master is sixteen revolutions per minute, the former may, in thetransferring process, be rotated at a shaft speed of forty revolutionsper minute and the latter at a shaft speedof eight revolutions perminute. By thus correspondingly reducing the surface speeds of themaster records and the micro-master, I am able to substantially reducedistortion effects due to inertia.

As I have stated, the master records which I make in the first place,preferably correspond with the present standards as to the shaft speed,surface speed and amplitude and in makm my improved micro-record, Iprefer to re uce the amplitude to substantially the same extent that thewidth and surface speed of my improved micro-record depart from standardpractice. Drawing an analogy from a pantograph, in other words, I

reduce all the dimensions of the copy which is being made from theoriginal. In t is way, I substantially reduce any loss in definition inthe copy due to lost motion or other energy losses in the completesystem.

Finally with my improved method, I prefer to make use of one or morethermionic amplifiers, whereby very feeble telephone currents, developedby the electrical pick-up may be amplified to any desired extent for theactuation of the magnetic recording mechanism. Thus it becomes possibleto make use of pickups in which excessively minute telephone currentsare developed and which respond with great accuracy to the soundvariations recorded on the original masters.

In order that my invention may be better understood, attention isdirected to the accompanying drawing, showing in diagram my improvedapparatus, designed to carry the method into effect.

The turntables 1 and 2 are driven in any suitable and usual way,preferably by electric motors (not shown of sufficient power to permiteither turnta le, when started, to very quickly reach its operatingspeed.

3 is a record on turntable 1 and 4 is a record on turntable 2. Theserecords may be either original'masters representing two successiveportions of the complete matter to be transferred to the micro-master orthey may be copies thereof .in hard material made in the usual way.

5 is an' electrical pick-up mechanism cooperating with the records 3 and6 and a similar pick-up mechanism cooperating with record 4. Both ofthese pick-up mechanisms are shown as being carried by pivoted arms 77so as to be fed across the respective record with which it cooperates.

The pick-up mechanisms are of any suitable and desired type for thedevelopment of telephone currents corresponding with the recordedsounds. They may operate upon any desired principle, such as by variableresistance or upon the principle of a magnetic telephone or condensertelephone, all of which are well known. pick-up operating upon either ofthe latter principles will be responsive with great accuracy to therecorded sounds, but the currents developed will be extremely feeble.This difficulty may be remedied by the use of thermionic amplifiers, asI will hereafter describe, whereby the currents may be amplified withoutdistortion to any desired value.

The pick-up 5 is shown as engaging the beginning of t 'e groove on therecord 3 and it is therefore assumed that that turntable 1 has just beenstarted so as to transfer the matter on record 3 to the micro-master.The pick-up 6 is shown in enga ement with the termination of the groove0 record 4 and it is therefore assumed that the turntable 2 has justbeen stopped.

The stopping of one turntable and the starting of the other may beperformed simultaneously at a single operation. As an illustration ofmechanism for this purpose, I show a brake shoe 8 adapted to cooperatewith the turntable 1 and a brake shoe 9 adapted to cooperate with theturntable 2, these brake shoes being connected by a rod 10 and operatedby a handle 11. The latter is adapted to be locked in either position bya spring latch 12 engaging two notches 1313, as will be obvious. Thus byswinging the handle 11 to the left the brake shoe 9 will be disengagedfrom the turntable 2 to permit the latter to start and will be engagedwith the turntable 1 to stop it. I

During the time the pick-up 5 is traversing the record 3, the operatorwill have an opportunity to remove the record 4 on the turntable 2 andreplace it with a record which succeeds the matter on record 3, andreturn the pick-up 6 to the starting position on the succeeding record.I

I show a circuit 14 for pick-up 5, leading to switch contacts 15, 15 anda corresponding :ircuit 16 for pick-up 6 leading to switch contacts 17,17. An ordinary two blade switch 18 is adapted to connect either of thecircuits 14 or 16 with a common circuit 19 having a battery 20 therein.

I preferably employ one or more thermionic amplifiers, to amplify thetelephone currents and in the drawing I show two of such amplifiersarranged in cascade in a well known way. The circuit 19 includes theprimary of a step-up transformer 21, the secondary ofwhich connectswith-the grid of a three-electrode vacuum tube 22. The plate circuit ofthis vacuum tube includes the primary of a step-up transformer 23, thesecondary of which leads to the grid of a second three-electrode vacuumtube 24. The plate circuit of the latter vacuum tube includes theprimary of a step-down transformer 25, the secondary of which isincluded in a circuit 26, which includes a magnetic recording mechanismof any suitable type, such as shown for example in my Patent No.1,544,37 9, dated Januar 30th, 1925. a

The -batteries 28, 28 supply current of the desired voltage to the platecircuits of the vacuum tubes.

The armature 29 of the magnetic recording mechanism carries a finepointed cutting tool 30, such armature being so pivoted, as shown, thatthe amplitude of the'cut will be substantially less than the maximumswing of said i armature. In other words, the armature is pivoted so astopartake substantially of the amplitude of the record groove on therecords 3 and 4, while the cutting stylus 30 will partake of a greatlyreduced amplitude. If the width of the record groove is one-fifth thewidth of a standard oove and if the mean surface speed is onefth of astandard groove, then I prefer to so pivot the armature 29 as to securean amplitude in the neighborhood ofone-fifth that of a standard roove.

The cutting stylus 30 cooperates with the micro-master 31, carried onthe turntable 32, whereby the' original records alternately placed onthe turntables 1 and 2 will be succersively transferred and recordedupon the micro-master 31. Itwill be, of course, understood that theshaft speed of turntable 32 and the pitch of the record groove formed bythe cutting stylus 30, will be substantiall reduced from those ofstandard ractice as have described in my patents first referred toherein.

In order that the operation of the switch 18 may be effectedconcurrently with the start and stopping of the respective turntables 1and 2, I show a connection 33 between the handle 11 and said switch sothat when the handle is moved the switch will be operated. Thus when thehandle 11 is moved to the left tostart the turntable 2 and stop theturntable 1, the switch 18 will be moved into engagement with thecontacts 17, 17 so as to connect the pick-up 6 with the battery circuit,19.

Having now described my invention, what I claim as new therein anddesire to secure by Letters Patent is as follows I 1. The method ofrecording sounds of long duration which consists in making successiverecords, each representing a fraction of the sounds to be recorded andin electrically transferring the recorded sounds from the successiverecords to a micro-blank turning at slower speed than the originalrecords, substantially as set forth.

2. The method of recording sounds of long duration which consists inmaking a series of .records each representing a fraction 'of the soundsto be recorded, said record being of substantial width and inelectrically transferring the sounds recorded on the successive recordsto a micro-master and forming a groove therein of greatly reduced width,substantially as set forth. I

3.' The method of recording sounds of long duration which consistsinmaking a series of records each representing a fraction of the soundsand being of substantial width and recorded at a substantial surfacespeed and in electrically transferring the sounds recordedon thesuccessive records to a micromaster and forming a groove therein ofgreatly reduced width and speed,'substantially as set forth.

4. The method of recording sounds of long .duration which consists inmaking a series of records each representing a fraction of the soundsand of substantial width and amplitude and in electrically transferringthe sounds recorded on the successive records to a micro-master andforming a groove therein of greatly reduced width and amplitude,substantially as set forth.

5. The method of recording sounds of long duration which consists inmaking a series of records each representing a fraction of the soundsand being of substantial width, surface speed and amplitude and inelectrically transferring the sounds recorded on the successive recordsto a micro-master and forming a groove therein of greatly reduced width,surface speed and amplitude, substantially as set forth.

6. The method of recording sounds of long duration which consists inmaking successive records each representing a fraction of the sounds tobe recorded, in playing said records in succession at a substantiallyreduced speedand in electrically transferring the recorded sounds fromthe successive records to a micro-blank turning at a substantiallyslower speed than the original record, substantially as set forth.

7. The method of recording sounds of long duration which consists inmaking successive records each representing a fraction of the sounds tobe recorded, in playing said records in succession and causing the saidrecords to generate telephone currents,'in amplifying said telephonecurrents, and in causing the amplified telephone currents to form, in amicro-master, a single sound groove representing the total soundsrecorded on the success ive. records, substantially as set forth.

- FRANK L. DYER.

